Apparatus for liquefying paraffin in wells



March 4, 1952 P. H. NASH 2,587,879

APPARATUS FOR LIQUEFYING PARAFFIN IN WELLS Filed Feb. 4, 1949 If A 7.5-

A TTORNEY Patented Mar. 4, 1952 APPARATUS FOR LIQUEFYIN G PARAFFIN IN WELLS Paul H. Nash, White Deer, Tex.

Application February 4, 1949, Serial No. 74,541

3 Claims. 1

This invention relates to parafiin extractors for oil wells and more particularly to apparatus for removing paraifln deposits from the walls of tubing without interrupting pumping operations.

The principal object 01 the invention is to provide a device adapted to be incorporated in the string of tubing in a well above the traveling valve therein and which is itself equipped with a novel form of heat sensitive valve by which steam introduced into the casing surrounding the tubing is caused to enter the latter and thus liquefy the paraffin coating the walls of the tubing, permitting the liquid parafiin to be elevated and discharged from the well by the pump, along with the oil. In this manner, paraflin deposits are carried out of the tubing without suspending the operation of the pump and are not permitted to precipitate in the tubing below the pump to again congeal and reduce the yield of the well.

Another object of the invention is to provide a paraiiin extractor for wells in which the valve for opening the tubing to ingress of steam consists of a tubular element surrounding the tubular body of the device and which is composed of a metal having a higher coefiicient of expansion than the tubular body and when heated by steam entering the space between the casing and tubing, will elongate sufficiently to bring into register a group of ports in a sleeve carried by the lower end of the element, with a like number of ports in the tubular body of the device which is incorporated in the tubing string in a well. When introduction of steam is suspended, the tubular element will resume its normal length, thereby clos ng the ports in the tubing.

With the foregoing obiects in view, the invention has further reference to certain features of accomplishment which will become apparent as the description proceeds, taken in connection with the accompanying drawings wherein:

Fi ure 1 is an elevational view of the invention shown incorporated in the tubing of a well.

Figure 2 is an elevational view of the invention, per se, partly in section and on a slightly larger scale.

Figure 3 is a view similar to Figure 2 but showing the tubular element of the valve elongated, and

Figure 4 is a transverse sectional view taken on line l--4 of Figure 3.

Continuing with a more detailed description of the drawing, reference numeral I denotes the casing of a well into which is suspended the string of tubing II. The sucker rod string is indicated by reference numeral I2 in Figure l and operates to actuate the conventional pump (not shown) in the tubing II.

Many and varied devices and methods have been used with indifferent success to minimize paramn trouble in wells. Mechanical means employed for the purpose include scrapers and the like while temporary relief has been attained by various forms of heaters. Some methods employ steam for liquefying the paraffin but in all of these, pumping must be suspended and in cases where ball check valves are employed, the valves are frequently fouled by congealing paraffin and it therefore becomes necessary to pull the valve for cleaning, which results in further pumping losses. This is true also where the tubing is required to be pulled to remove from its walls the coating of paraffin which has reduced the yield of the well. These methods and devices offer but temporary relief and require expensive shutdowns.

The invention seeks to provide a medium by which the congealed paraiiin may be periodically removed from the tubing before its presence therein becomes a serious impediment to normal pumping operations and to accomplish this while pumping is proceeded with.

With the foregoing in view the invention consists of a tubular body I3 whose inner diameter is the same as that of the tubing II. This member is exteriorly threaded at each. end to be received by the threaded ends of couplings I4, each of which latter is provided with an annular flange I5, slightly less in diameter than the inside diameter of the casing I 0. Into the opposite end of each coupling I4 is threaded an end of a section of tubing ll. Thus, the tubular body I3 is incorporated in the length of the tubing string and disposed at a level in the well at which paraffin is most likely to congeal. In any case, the pump operates in the tubing at a point below the tubular body I3 to insure a condition which will become evident presently.

Surrounding the tubular body I3 in close ,slidable enga ement is an elongated tubular element [6. This element I 6 is formed from a metal having a higher coefficient of expansion than that of the tubular body and has on its upper end threads numbering preferably four to the inch to engage corresponding threads on the Number four threads are also provided for securing the tubular expansion element and sleeve I8 together for the same reason as explained above and a set screw l9 prevents separation of these parts during expanded periods of the element [6.

register a group of circumferential ports 20 in the sleeve IS with a like number of similarlyar ranged ports 2| in the tubular body l3 and thus to provide opening of sufiicient area to admit steam into the tubing in adequate volume to reduce to liquid the parafiln solids ocating" the walls interiorly of the tubing H.

It will be observed in Figure 1 that the flanges of couplings M are smaller in diameter than the casing H3 yet'will protectthe-expansion element 16 against damage and yet will not interhere with downward passage of steam introduced into the casing through pipe 22 at the surface; As the expansion element l' becomes" heated in the p're'senceofthe steam it elongates and moves the sleeve 18 downwardly where thep'orts 20 thereof will eventuallycome into registerwith ports" 2| of the tubular body I32 When this occurs it is evident that steam exteriorly of the tubing will enter the latter through the ports 29 and 2I'to heat'the paraffin deposits within the tubing, causing the same to return to=liquid form. It is also apparent that operation of the pump withinthe tubing l I need not be suspended during injection of steam since the ingress of steamat the ports 2fl-'2I' willprevent' escape of oil therethrough, although this would benegligiblei As'a matter of iact'continuous operation of thepu'mp is preferred since the paraflin inliquid form is easily pumped out of thew'ell into the flow tank with the oil.

Manifestly, the'construction as shown andd'escribed is capable ofsome modificationa'nd'such modification as may be construed to fall within the scope and meaning of' th'eap'pen'ded' claims is also consideredto be Within the spiritand intent of the invention.

What is claimed is:

1. In a paraffin extractor for case'd' wells; an

elongated tubular body incorporated in the length of the tubing stringin a well and'compo'sed of a' material having a low c'oefiicient' of expansion, said body having circumferentially spaced ports therein adjacent its lower end', a tubular expansion element surrounding said body and com} posed of a metal having a high'co'efiicient of expansion, said tubular expansion element being in fixed relationship with saidtubular body at its'upper end, a sleeve attachedto the lower end of said tubular expansion element, slidab'le on said tubular body and having ports 'aligna'ble with those of said tubular body and means for introducing steam into the casing of" saidwell,

the difference in coefficient of expansion between said tubular expansion element and said body being sufiicient under the temperature of said steam to cause said expansion element to expand and to bring into register the ports of said sleeve and body for the admission of steam into said body and tubing string.

2. In avparaffin extractor for a cased oil well, a tubular body of low coefficient of expansion incorporated in the length of tubing string in said well and having ports therein adjacent its lower end, a'tubular element of relatively high coefiicient of expansion embracing said tubular body, means securing said tubular element at its upper end in fixed relation to said body, a sleeve aiiixed to the lower end of said tubular element and slidably embracing said body, said sleeve' having ports alignable with those of said tubular body, the coefficient'of expansion of 'said tubular body being sufficiently different from that of said tubular element to effect a differ ential degree of expansion of said body and said element in the presence of heat to cause alignment of said alignable ports and means for in= troducing steam into the casing of said Well to expand said tubular element and effect align"- ment of said ports to admit steam into said tubular body and tubing strin'gthrough said aligned ports.

3. In an apparatus for liquefying' congealed paraffin in the tubing string ofacased oil well during pumping thereof, an elongated tubular body of low coefficient ofe'xpansion"incorporated in the length of said tubing string andh'aving ports therein, a tubular element" of amaterial having relatively high ooe'fiicient' of ex ansion surrounding said body and in fixed relationthere with at its upper end, a sleeve connected-to said tubular element and having ports adapted to register withrthoseof said body" when saidtubular body and said tubularelement'are exposed to high ternperaturesto"expandsaid tubular ele= ment on said body and means for'introducing steam into the casing of said well to expand said tubular element to effect registration of said ports and admit" steam" interiorly of said body and tubing string.

PAUL H. NASH:

REFERENCES CITE-D" The following references are of recordinthe file of this patent: V UNITED STATES PATENTS White "Jan; 6,1942 

1. IN A PARAFFIN EXTRACTOR FOR CASED WELLS, AN ELONGATED TUBULAR BODY INCORPORATED IN THE LENGTH OF THE TUBING STRING IN A WELL AND COMPOSED OF A MATERIAL HAVING A LOW COEFFICIENT OF EXPANSION, SAID BODY HAVING CIRCUMFERENTIALLY SPACED PORTS THEREIN ADJACENT ITS LOWER END, A TUBULAR EXPANSION ELEMENT SURROUNDING SAID BODY AND COMPOSED OF A METAL HAVING A HIGH COEFFICIENT OF EXPANSION, SAID TUBULAR EXPANSION ELEMENT BEING IN FIXED RELATIONSHIP WITH SAID TUBULAR BODY AT ITS UPPER END, A SLEEVE ATTACHED TO THE LOWER END OF SAID TUBULAR EXPANSION ELEMENT, SLIDABLE ON SAID TUBULAR BODY AND HAVING PORTS ALIGNABLE WITH THOSE OF SAID TUBULAR BODY AND MEANS FOR INTRODUCING STEAM INTO THE CASING OF SAID WELL, THE DIFFERENCE IN COEFFICIENT TO EXPANSION BETWEEN SAID TUBULAR EXPANSION ELEMENT AND SAID BODY BEING SUFFICIENT UNDER THE TEMPERATURE OF SAID STEAM TO CAUSE SAID EXPANSION ELEMENT TO EXPAND AND TO BRING INTO REGISTER THE PORTS OF SAID SLEEVE AND BODY FOR THE ADMISSION OF STEAM INTO SAID BODY AND TUBING STRING. 